CN104907069A - Catalyst for room temperature formaldehyde purification, and use thereof - Google Patents

Abstract

The invention relates to a catalyst for purifying formaldehyde at room temperature. The catalyst includes a porous inorganic oxide carrier and an active component and an auxiliary agent loaded on the carrier. The active component includes a transition metal active component. The transition The metal is any one or a combination of at least two of manganese, iron, ruthenium, iridium, osmium, nickel, copper or zinc. The catalyst for purifying formaldehyde at room temperature has simple conditions of use and is easy to operate, and can be effectively used to catalyze and oxidize formaldehyde, a major indoor pollutant, at room temperature. The catalyst can catalyze and oxidize formaldehyde into carbon dioxide and water at room temperature, without formic acid , carbon monoxide and methyl formate and other by-products, the conversion rate of formaldehyde can be as high as 100%.

Description

Catalyst and application thereof for purifying formaldehyde at room temperature

technical field

The invention relates to a catalyst, in particular to a catalyst for purifying formaldehyde at room temperature.

Background technique

With the improvement of people's material and cultural living standards, interior decoration has become fashionable, but indoor air pollution is also becoming more and more serious. Formaldehyde is one of the most typical and serious pollutants in the indoor environment. The concentration limit of formaldehyde pollutants in indoor air stipulated by China's national standards is 0.08mg/m ³ . At present, the concentration of formaldehyde in the indoor environment of our country exceeds the standard. According to the sampling survey conducted by the National Center for Disease Control and Prevention, more than 60% of the newly decorated residential buildings in my country have excessive formaldehyde concentration, which has caused great harm to people's health. With the improvement of environmental protection awareness, people are paying more and more attention to indoor formaldehyde pollution. In recent years, complaints caused by excessive indoor formaldehyde concentration have also been frequently reported. Therefore, it has become an urgent task to improve people's living environment to study formaldehyde purification technology and effectively eliminate indoor formaldehyde pollution.

The existing indoor formaldehyde purification technology is mainly based on adsorption technology and photocatalysis technology. Adsorption technology mainly uses high specific surface materials such as activated carbon and molecular sieves to adsorb formaldehyde. However, due to the limited adsorption capacity of the adsorption materials, it needs to be regenerated or replaced regularly, and it is easy to cause secondary pollution. Photocatalytic technology mainly uses nano- _TiO2 as a photocatalyst to decompose formaldehyde, but there are problems such as the need for ultraviolet excitation light source, low utilization efficiency of visible light, and easy deactivation of the catalyst. Non-photocatalytic oxidation purification of indoor formaldehyde does not require light or other energy input, and it can completely catalyze the oxidation of formaldehyde at room temperature to produce water and carbon dioxide final products. This technology has been widely promoted and applied.

CN101380574 discloses a catalyst for catalyzing complete oxidation of formaldehyde at room temperature. The catalyst is composed of a porous inorganic oxide carrier, a noble metal component and an auxiliary component. The porous inorganic oxide carrier is one or more mixtures of ceria, zirconia, titanium dioxide, aluminum oxide, tin dioxide, silicon dioxide, lanthanum oxide, magnesium oxide, and zinc oxide, or Its composite oxide, zeolite, sepiolite, porous carbon material, the catalyst precious metal component is at least one of platinum, rhodium, palladium, gold, silver, and the additive component is alkali metal lithium, sodium, potassium, rubidium, At least one of cesium. The loading amount of the precious metal component used in the catalyst of the invention is 0.1-10%, preferably 0.3-2%, based on the conversion of metal element weight; the loading amount of the auxiliary component is 0.2-30% based on the conversion of metal element weight , preferably 1-10%, when the loading of the auxiliary component is lower than 0.2% or higher than 30%, the activity of the catalyst for catalytic oxidation of formaldehyde at room temperature is significantly reduced.

CN1795970A provides a high-activity catalyst for catalyzing and completely oxidizing low-concentration formaldehyde at room temperature. The catalyst uses simple and easy-to-obtain metal oxides and a very small amount of precious metals as raw materials, and the preparation method is simple. The catalyst is mainly composed of metal oxides, and noble metal components are supported on the metal oxides. The aforementioned metal oxide component may be at least one of the following metal oxide groups, and the aforementioned noble metal component may be at least one of the following noble metal groups. Metal oxides: ceria, zirconia, titanium dioxide, aluminum oxide, lanthanum oxide, magnesium oxide, zinc oxide, calcium oxide, copper oxide; precious metals: platinum, gold, rhodium, palladium, silver. The catalyst of the invention is composed of ordinary metal oxides and a small amount of precious metals, and can be effectively applied to the catalytic oxidation of formaldehyde at room temperature. The catalyst of the invention has high catalytic activity and long duration, the conversion rate of formaldehyde can be as high as 100% at room temperature, and the products are carbon dioxide and water.

CN102941111A discloses a catalyst supported by a metal carrier for room temperature formaldehyde purification, the catalyst is composed of a metal carrier, a porous inorganic material loaded on the metal carrier, a noble metal active component and an auxiliary agent loaded on the porous inorganic material, The metal carrier is an iron-chromium-aluminum alloy, the noble metal is selected from any one or a mixture of at least two of platinum, rhodium, palladium, gold or silver, and the auxiliary agent is an alkali metal element, an alkali metal compound, an alkaline earth Any one of metal element or alkaline earth metal compound or a mixture of at least two.

However, the above-mentioned prior art catalysts are expensive, have poor moisture resistance, and have poor stability.

Contents of the invention

In view of the problems in the prior art, one object of the present invention is to provide a catalyst for purifying formaldehyde at room temperature, which has excellent moisture resistance and stability under the premise of maintaining catalytic efficiency.

In order to achieve the above object, the present invention adopts following technical scheme:

A catalyst for purifying formaldehyde at room temperature, the catalyst includes a carrier, an active component and an auxiliary agent, the carrier is a porous inorganic oxide carrier, the active component includes a transition metal active component, and the transition metal is Any one or a combination of at least two of manganese, iron, ruthenium, iridium, osmium, nickel, copper or zinc.

Preferably, the specific surface area of the porous inorganic oxide support is 10-1000m ² /g, such as 20m ² /g, 50m ² /g, 100m ² /g, 200m ² /g, 300m ² /g, 400m ² /g g, 500m ² /g, 600m ² /g, 700m ² /g, 800m ² /g or 900m ² /g, preferably 50-400m ² /g, more preferably 60-180m ² /g. Selecting the specific surface area of the preferably porous inorganic oxide carrier can significantly improve the stability of the catalyst on the premise of ensuring its excellent catalytic activity.

Preferably, the particle size of the porous inorganic oxide carrier is 2-200nm, such as 10nm, 20nm, 40nm, 60nm, 80nm, 100nm, 120nm, 140nm, 160nm or 180nm, preferably 10-100nm, more preferably 20- 60nm. Selecting the preferred particle size can significantly improve the moisture resistance and stability of the catalyst.

Preferably, the porous inorganic oxide carrier is ceria, zirconia, titanium dioxide, aluminum oxide, tin dioxide, silicon dioxide, lanthanum oxide, manganese oxide, iron oxide, calcium oxide, magnesium oxide Or any one of zinc oxide or a mixture of at least two or a composite of at least two, preferably any one of titanium dioxide, aluminum oxide or silicon dioxide or a mixture of at least two.

The mixture refers to a substance obtained by physically mixing various substances.

The composite refers to a multi-metal component oxide prepared by chemical methods.

Preferably, the porous inorganic oxide can also be zeolite, sepiolite or porous carbon material.

Preferably, the transition metal active component is the metal or an oxide of the metal or an inorganic salt of the metal.

Preferably, the transition metal is any one or a combination of at least two of manganese, iron, ruthenium or iridium, preferably a combination of manganese-iridium, iron-ruthenium or iron-iridium. Selecting the preferred combination of transition metals can significantly improve the moisture resistance and stability of the catalyst under the premise of ensuring the catalytic activity of the catalyst.

Based on the weight of the catalyst as 100%, the transition metal is manganese, iron, nickel, copper or zinc, and the transition metal active component is based on the weight of the transition metal element, and the weight percentage of the transition metal active component is 0.1 to 50%, such as 0.5 %, 1.2%, 1.8%, 2.4%, 3.2%, 3.8%, 4.5%, 6.1%, 6.9%, 7.2%, 7.8%, 8.4%, 9.2%, 9.6%, 10.5%, 12.3%, 14.6%, 15.8%, 17.9%, 20.6%, 24.3%, 26.8%, 30.1%, 32.6%, 35.7%, 39.4%, 41.5%, 43.8%, 46.9%, 48.7% or 49.6%, preferably 10-30%, more preferably 12 to 25%, more preferably 15 to 20%.

Based on the weight of the catalyst as 100%, the transition metal is ruthenium, iridium or osmium, and the transition metal active component is based on the weight of the transition metal element, and the weight percentage of the transition metal active component is 0.1 to 10%, such as 0.5%, 1.2%. , 1.8%, 2.4%, 3.2%, 3.8%, 4.5%, 6.1%, 6.9%, 7.2%, 7.8%, 8.4%, 9.2%, 9.6%, more preferably 0.2-8%, still more preferably 0.3-3 %.

Preferably, the transition metal is a combination of manganese and iridium, and the molar ratio of manganese and iridium is 0.01 to 0.09, such as 0.02, 0.03, 0.04, 0.05, 0.06, 0.07 or 0.08, preferably 0.02 to 0.04, based on the weight of the catalyst In terms of 100%, the transition metal active component is based on the weight of the transition metal element, and the weight percentage of the transition metal active component is 0.1 to 10%, such as 0.5%, 1.2%, 1.8%, 2.4%, 3.2%, 3.8%, 4.5%, 6.1%, 6.9%, 7.2%, 7.8%, 8.4%, 9.2%, 9.6%.

Preferably, the transition metal is a combination of iron and ruthenium, and the molar ratio of iron and ruthenium is 0.01 to 0.09, such as 0.02, 0.03, 0.04, 0.05, 0.06, 0.07 or 0.08, preferably 0.02 to 0.03, based on the weight of the catalyst In terms of 100%, the transition metal active component is based on the weight of the transition metal element, and the weight percentage of the transition metal active component is 0.1 to 10%, such as 0.5%, 1.2%, 1.8%, 2.4%, 3.2%, 3.8%, 4.5%, 6.1%, 6.9%, 7.2%, 7.8%, 8.4%, 9.2%, 9.6%.

Preferably, the transition metal is a combination of iron and iridium, and the molar ratio of iron and iridium is 0.01 to 0.09, such as 0.02, 0.03, 0.04, 0.05, 0.06, 0.07 or 0.08, preferably 0.02 to 0.03, based on the weight of the catalyst In terms of 100%, the transition metal active component is based on the weight of the transition metal element, and the weight percentage of the transition metal active component is 0.1 to 10%, such as 0.5%, 1.2%, 1.8%, 2.4%, 3.2%, 3.8%, 4.5%, 6.1%, 6.9%, 7.2%, 7.8%, 8.4%, 9.2%, 9.6%.

Preferably, the auxiliary agent is any one or a combination of at least two of the oxides or hydroxides of alkali metals or alkaline earth metals, and the weight percentage of the auxiliary agent component is 0.1 based on the weight of the catalyst as 100%. ~40%, more preferably 0.5~20%, still more preferably 2~10%.

The preparation method of the metal carrier-supported catalyst used for room temperature formaldehyde purification is a prior art, and those skilled in the art can prepare the above-mentioned catalyst according to the preparation method of the catalyst disclosed in the prior art.

The exemplary preparation method of the catalyst for purifying formaldehyde at room temperature comprises the following steps:

Impregnation method: impregnate the porous inorganic oxide carrier in the aqueous solution of the soluble compound of transition metal and auxiliary metal, stir for 1-5 hours, dry at 80-120°C, and place in a muffle furnace under the condition of air, nitrogen or hydrogen Baking at 200-700°C for 1-8 hours.

The catalyst of the present invention can be made into various structures according to different needs, such as being loaded on the wall surface of a honeycomb ceramic body or a mesh structure made of metal, and the open-cell foam body can also be used as a structural carrier of the catalyst. In addition, the catalyst can also be used in a spherical or plate shape. The specific process of loading the above-mentioned catalyst on the honeycomb ceramic carrier is: first, mix the prepared catalyst and deionized water to form a mixture with a certain solid content concentration, and then perform ball milling on the above-mentioned mixed solution to form a mixture with a certain solid content and viscosity. , specific gravity, catalyst particles and pH slurry, and then coated, dried and calcined to obtain monolithic catalyst.

The second object of the present invention is to provide the use of the above-mentioned catalyst for purifying formaldehyde at room temperature, which is used for purifying formaldehyde at room temperature.

Preferably, the method that catalyst is used for room temperature formaldehyde purification comprises the steps:

First, the powder catalyst is molded to obtain a catalytic purification formaldehyde module, and then assembled to form a catalytic purification formaldehyde component, which is then placed in an air purifier or other air purification device, and the polluted gas containing formaldehyde passes through the above device under the disturbance of the air , and contact with the catalytic purification component, so as to realize the purification of formaldehyde at room temperature.

Compared with the prior art, the present invention has the following beneficial effects:

The catalyst used for purifying formaldehyde at room temperature has high catalytic efficiency, low energy consumption after being assembled in purifying equipment, and low cost.

The catalyst for purifying formaldehyde at room temperature has simple conditions of use and is easy to operate, and can be effectively used to catalyze and oxidize formaldehyde, a major indoor pollutant, at room temperature. The catalyst can catalyze and oxidize formaldehyde into carbon dioxide and water at room temperature, without formic acid , carbon monoxide and methyl formate and other by-products, the conversion rate of formaldehyde can be as high as 100%.

The catalyst can reach 100% formaldehyde conversion rate at room temperature and under normal humidity (humidity 50%) conditions, and the formaldehyde catalytic conversion rate is very high under high humidity (≥90%) environment, which can still maintain More than 90% conversion rate. Moreover, the catalyst has high stability. At room temperature and under normal humidity conditions, within 500 hours, the formaldehyde conversion rate can reach 95% and above; The rate can still reach more than 85%. Therefore, the catalyst has excellent stability and moisture resistance.

Detailed ways

For better illustrating the present invention, facilitate understanding technical scheme of the present invention, typical but non-limiting embodiment of the present invention is as follows:

Example 1

A catalyst for purifying formaldehyde at room temperature, the catalyst is composed of a porous inorganic oxide, a transition metal active component and an auxiliary agent supported on the porous inorganic oxide, the porous inorganic oxide is cerium oxide, and its ratio The surface area is 10m ² /g, the particle size is 30nm, the active component is manganese-iridium composite oxide, the molar ratio of manganese and iridium is 0.03, the catalyst weight is 100%, and the transition metal active component is transition metal On the basis of element weight, the weight percentage of the transition metal active component is 5%, the auxiliary agent is barium oxide, and the auxiliary agent content is 8%.

Example 2

The rest are the same as in Example 1, except that the specific surface area is 1000m ² /g.

Example 3

The rest are the same as in Example 1, except that the specific surface area is 60m ² /g.

Example 4

The rest are the same as in Example 1, except that the specific surface area is 180m ² /g.

Take 60mg of the catalysts of Examples 1-4 respectively and place them in a tubular fixed-bed reactor for experiments. The experimental conditions are as follows: 20% oxygen, 80% helium, and formaldehyde gas is generated by a formaldehyde gas generator, which is blown into the reaction by helium. For the system, the concentration of formaldehyde is controlled at 0.01%, the relative humidity is 50%, the reaction space velocity (GHSV) is 50000h ^-1 , and the reaction temperature is room temperature. The activity evaluation results are shown in Table 1.

Table 1

Take 60mg of the catalysts of Examples 1-4 respectively and place them in a tubular fixed-bed reactor for experiments. The experimental conditions are as follows: 20% oxygen, 80% helium, and formaldehyde gas is generated by a formaldehyde gas generator, which is blown into the reaction by helium. In the system, the concentration of formaldehyde is controlled at 0.01%, the relative humidity is 50%, the reaction space velocity (GHSV) is 50000h ^-1 , and the reaction temperature is room temperature. The catalysts of Examples 1 and 2 maintained the formaldehyde conversion rate above 90% within 500 hours, and the catalysts of Examples 3-4 maintained the formaldehyde conversion rate above 95% within 500 hours.

Take 60 mg of the catalysts of Examples 1 to 4 respectively, and place them in a tubular fixed-bed reactor for the experiment. The experimental conditions are as follows: formaldehyde gas is generated by a formaldehyde gas generator, blown into the reaction system by helium, and the formaldehyde concentration is controlled to be 0.01%. The relative humidity ranges from 50% to 90%, the reaction space velocity (GHSV) is 50000h ^-1 , and the reaction temperature is room temperature. The activity evaluation results are shown in Table 2.

Table 2 Catalyst activity evaluation results

Take 60mg of the catalysts of Examples 1-4 respectively and place them in a tubular fixed-bed reactor for experiments. The experimental conditions are as follows: 20% oxygen, 80% helium, and formaldehyde gas is generated by a formaldehyde gas generator, which is blown into the reaction by helium. In the system, the concentration of formaldehyde is controlled at 0.01%, the relative humidity is 90%, the reaction space velocity (GHSV) is 50000h ^-1 , and the reaction temperature is room temperature. For the catalysts of Examples 1 and 2, the formaldehyde conversion rate has been maintained above 60% within 500 hours, and for the catalysts of Examples 3-4, the formaldehyde conversion rate has been maintained above 90% within 500 hours.

The above Examples 1-4 illustrate that the porous inorganic oxide carrier has an influence on the catalytic activity and stability of the catalyst. When the catalyst is selected to be 60-180 m ² /g, the catalytic activity and stability of the catalyst are significantly improved.

Example 5

The rest are the same as in Example 1, except that the particle size of ceria is 2nm.

Example 6

The rest are the same as in Example 1, except that the particle size of ceria is 200nm.

Example 7

The rest are the same as in Example 1, except that the particle size of ceria is 20nm.

Example 8

The rest are the same as in Example 1, except that the particle size of ceria is 60nm.

Take 60mg of the catalysts of Examples 5-8 respectively and place them in a tubular fixed-bed reactor for experimentation. The experimental conditions are as follows: 20% oxygen, 80% helium, and formaldehyde gas is generated by a formaldehyde gas generator, which is blown into the reaction by helium. For the system, the formaldehyde concentration was controlled at 0.01%, relative humidity at 50%, reaction space velocity (GHSV) at 50000h ^-1 , and reaction temperature at room temperature. The activity evaluation results are shown in Table 3.

table 3

Take 60mg of the catalysts of Examples 5-8 respectively and place them in a tubular fixed-bed reactor for experimentation. The experimental conditions are as follows: 20% oxygen, 80% helium, and formaldehyde gas is generated by a formaldehyde gas generator, which is blown into the reaction by helium. In the system, the concentration of formaldehyde is controlled at 0.01%, the corresponding humidity is 50%, the reaction space velocity (GHSV) is 50000h ^-1 , and the reaction temperature is room temperature. For the catalysts of Examples 5 and 6, the formaldehyde conversion rate has been maintained above 90% within 500 hours, and for the catalysts of Examples 7 and 8, the formaldehyde conversion rate has been maintained above 95% within 500 hours.

Take 60 mg of the catalysts of Examples 5-8 respectively, place them in a tubular fixed-bed reactor and carry out the experiment. The experimental conditions are as follows: formaldehyde gas is generated by a formaldehyde gas generator, blown into the reaction system by helium, and the formaldehyde concentration is controlled to be 0.01%. The relative humidity ranges from 50% to 90%, the reaction space velocity (GHSV) is 50000h ^-1 , and the reaction temperature is room temperature. The activity evaluation results are shown in Table 4.

Table 4 Catalyst Activity Evaluation Results

Take 60mg of the catalysts of Examples 1-4 respectively and place them in a tubular fixed-bed reactor for experiments. The experimental conditions are as follows: 20% oxygen, 80% helium, and formaldehyde gas is generated by a formaldehyde gas generator, which is blown into the reaction by helium. In the system, the concentration of formaldehyde is controlled at 0.01%, the corresponding humidity is 90%, the reaction space velocity (GHSV) is 50000h ^-1 , and the reaction temperature is room temperature. For the catalysts of Examples 5 and 6, the formaldehyde conversion rate has been maintained above 65% within 500 hours, and for the catalysts of Examples 7 and 8, the formaldehyde conversion rate has been maintained above 90% within 500 hours.

The above Examples 1 and 5-8 show that the particle size of the porous inorganic oxide carrier has an influence on the catalytic activity and stability of the catalyst. When the particle size is 20-60nm, the catalytic activity and stability of the catalyst are significantly improved.

Example 9

The rest are the same as in Example 1, except that the transition metal active component is an iron-ruthenium composite oxide, and the mol ratio of the iron to ruthenium is 0.03, and the weight of the catalyst is 100%, and the transition metal active component is by transition metal element weight Calculated, the weight percent of the transition metal active component is 5%.

Example 10

The rest are the same as in Example 1, except that the transition metal active component is an iron-iridium composite oxide, and the mol ratio of the iron to iridium is 0.03, and the weight of the catalyst is 100%, and the transition metal active component is by transition metal element weight Calculated, the weight percent of the transition metal active component is 5%.

Example 11

All the other are the same as Example 1, except that the active component is nickel.

Example 12

All the other are the same as Example 1, except that the active component is copper.

Example 13

All the other are identical with embodiment 1, except active component is zinc.

Take 60mg of the catalysts of Examples 9-13 respectively and place them in a tubular fixed-bed reactor for experiments. The experimental conditions are as follows: 20% oxygen, 80% helium, and formaldehyde gas is generated by a formaldehyde gas generator, which is blown into the reaction by helium. For the system, the concentration of formaldehyde was controlled at 0.01%, the relative humidity was 50%, the reaction space velocity (GHSV) was 50000h ^-1 , and the reaction temperature was room temperature. The activity evaluation results are shown in Table 5.

table 5

Take 60mg of the catalysts of Examples 9-13 respectively and place them in a tubular fixed-bed reactor for experiments. The experimental conditions are as follows: 20% oxygen, 80% helium, and formaldehyde gas is generated by a formaldehyde gas generator, which is blown into the reaction by helium. In the system, the concentration of formaldehyde is controlled at 0.01%, the relative humidity is 50%, the reaction space velocity (GHSV) is 50000h ^-1 , and the reaction temperature is room temperature. For the catalysts of Examples 9 and 10, the formaldehyde conversion rate has been maintained above 95% within 500 hours, and for the catalysts of Examples 11-13, the formaldehyde conversion rate has been maintained above 85% within 500 hours.

Take 60 mg of the catalysts of Examples 9 to 13 respectively, and place them in a tubular fixed-bed reactor for experimentation. The experimental conditions are as follows: formaldehyde gas is generated by a formaldehyde gas generator, blown into the reaction system by helium, and the formaldehyde concentration is controlled to be 0.01%. The relative humidity ranges from 50% to 90%, the reaction space velocity (GHSV) is 50000h ^-1 , and the reaction temperature is room temperature. The activity evaluation results are shown in Table 6.

Table 6 Catalyst Activity Evaluation Results

Get respectively 60mg embodiment 9～13 catalyst, be placed in the tubular fixed-bed reactor and carry out experiment, experiment condition is as follows: oxygen 20%, helium 80%, relative humidity 90%, formaldehyde gas produces with formaldehyde gas generator, by Helium gas was blown into the reaction system, the formaldehyde concentration was controlled to be 0.01%, the reaction space velocity (GHSV) was 50000h ^-1 , and the reaction temperature was room temperature. The catalysts of Examples 9 and 10 maintained the formaldehyde conversion rate above 90% within 500 hours, and the catalysts of Examples 11-13 maintained the formaldehyde conversion rate above 60% within 500 hours.

Comparative example 1

The rest are the same as in Example 1, except that the active component is a noble metal active component, and the noble metal is Ag.

Comparative example 2

The rest are the same as in Example 1, except that the specific surface area of the porous inorganic oxide carrier is 5 m ² /g.

Comparative example 3

The rest are the same as in Example 1, except that the specific surface area of the porous inorganic oxide carrier is 1100 m ² /g.

Comparative example 4

The rest are the same as in Example 1, except that the particle size of the porous inorganic oxide is 1 nm.

Comparative example 5

The rest are the same as in Example 1, except that the particle size of the porous inorganic oxide is 220 nm.

Comparative example 6

All the other are identical with embodiment 1, except that the mol ratio of manganese and iridium is 0.005.

Comparative example 7

All the other are identical with embodiment 1, except that the mol ratio of manganese and iridium is 0.10.

Comparative example 8

The rest are the same as in Example 9, except that the molar ratio of iron and ruthenium is 0.005.

Comparative example 9

The rest are the same as in Example 9, except that the molar ratio of iron and ruthenium is 0.10.

Comparative example 10

The rest are the same as in Example 10, except that the molar ratio of iron and iridium is 0.005.

Comparative example 11

The rest are the same as in Example 10, except that the molar ratio of iron and iridium is 0.10.

Take 60mg of the catalysts of comparative examples 1-11 respectively, and place them in a tubular fixed-bed reactor for experiments. The experimental conditions are as follows: 20% oxygen, 80% helium, and formaldehyde gas is generated by a formaldehyde gas generator, which is blown into the reaction by helium. For the system, the concentration of formaldehyde is controlled at 0.01%, the relative humidity is 50%, the reaction space velocity (GHSV) is 50000h ^-1 , and the reaction temperature is room temperature. The activity evaluation results are shown in Table 7 and Table 8.

Table 7

Table 8

Take 60mg of the catalysts of comparative examples 1-11 respectively, and place them in a tubular fixed-bed reactor for experiments. The experimental conditions are as follows: 20% oxygen, 80% helium, and formaldehyde gas is generated by a formaldehyde gas generator, which is blown into the reaction by helium. In the system, the concentration of formaldehyde is controlled at 0.01%, the relative humidity is 50%, the reaction space velocity (GHSV) is 50000h ^-1 , and the reaction temperature is room temperature. For the catalysts of Comparative Examples 1-11, the conversion rate of formaldehyde was maintained above 75% within 500 hours.

Take 60mg of the catalysts of comparative examples 1-11 respectively, and place them in a tubular fixed-bed reactor for experimentation. The experimental conditions are as follows: formaldehyde gas is generated by a formaldehyde gas generator, blown into the reaction system by helium, and the formaldehyde concentration is controlled to be 0.01%. The relative humidity ranges from 50% to 90%, the reaction space velocity (GHSV) is 50000h ^-1 , and the reaction temperature is room temperature. The activity evaluation results are shown in Table 9.

Table 9 Catalyst Activity Evaluation Results

Take 60mg of the catalysts of comparative examples 1-11 respectively, and place them in a tubular fixed-bed reactor for experiments. The experimental conditions are as follows: 20% oxygen, 80% helium, and formaldehyde gas is generated by a formaldehyde gas generator, which is blown into the reaction by helium. In the system, the concentration of formaldehyde is controlled at 0.01%, the relative humidity is 90%, the reaction space velocity (GHSV) is 50000h ^-1 , and the reaction temperature is room temperature. For the catalysts of Comparative Examples 1-11, the conversion rate of formaldehyde was maintained above 50% within 500 hours.

The applicant declares that the present invention illustrates the detailed composition of the catalyst described in the present invention through the above examples, but the present invention is not limited to the above detailed composition, that is, it does not mean that the present invention must rely on the above detailed composition to be implemented. Those skilled in the art should understand that any improvement of the present invention, the equivalent replacement of each raw material of the product of the present invention, the addition of auxiliary components, the selection of specific methods, etc., all fall within the scope of protection and disclosure of the present invention.

Claims (10)

1. the catalyst for room temperature purifying formaldehyde, described catalyst comprises carrier, active component and auxiliary agent, described carrier is porous inorganic oxide carrier, described active component comprises transition metal active component, and described transition metal is the combination of any one or at least two kinds in manganese, iron, ruthenium, iridium, osmium, nickel, copper or zinc.

2. catalyst as claimed in claim 1, it is characterized in that, the specific area of described porous inorganic oxide carrier is 10 ~ 1000m ²/ g, is preferably 50 ~ 400m ²/ g, more preferably 60-180m ²/ g.

3. catalyst as claimed in claim 1 or 2, it is characterized in that, the particle diameter of described porous inorganic oxide carrier is 2-200nm, is preferably 10-100nm, more preferably 20-60nm.

4. the catalyst as described in one of claim 1-3, it is characterized in that, described porous inorganic oxide carrier is any one or the mixture of at least two kinds in ceria, zirconium dioxide, titanium dioxide, alundum (Al2O3), tin ash, silica, lanthanum sesquioxide, manganese oxide, iron oxide, calcium oxide, magnesia or zinc oxide or the compound of at least two kinds, and preferred described porous inorganic oxide carrier is the mixture of any one or at least two kinds in titanium dioxide, alundum (Al2O3) or silica.

5. the catalyst as described in one of claim 1-3, is characterized in that, described porous inorganic oxide is also zeolite, sepiolite or porous Carbon Materials.

6. the catalyst as described in one of claim 1-5, is characterized in that, described transition metal is the combination of any one or at least two kinds in manganese, iron, ruthenium or iridium, the combination of the combination of preferred manganese iridium, the combination of iron ruthenium or iron iridium.

7. the catalyst as described in one of claim 1-6, is characterized in that, transition metal active component is the oxide of this metal or this metal or the inorganic salts of this metal;

Preferably, in the weight of catalyst for 100%, transition metal is manganese, iron, nickel, copper or zinc, transition metal active component presses transition metal weighing scale, the percentage by weight of transition metal active component is 0.1 ~ 50%, preferably 10 ~ 30%, further preferably 12 ~ 25%, more further preferably 15 ~ 20%.

8. the catalyst as described in one of claim 1-7, it is characterized in that, in the weight of catalyst for 100%, transition metal is ruthenium, iridium or osmium, transition metal active component presses transition metal weighing scale, the percentage by weight of transition metal active component is 0.1 ~ 10%, further preferably 0.2 ~ 8%, more further preferably 0.3 ~ 3%;

Preferably, described transition metal is the combination of manganese iridium, the mol ratio of described manganese and iridium is 0.01 ~ 0.09, preferably 0.02 ~ 0.04, in the weight of catalyst for 100%, transition metal active component presses transition metal weighing scale, and the percentage by weight of transition metal active component is 0.1 ~ 10%;

Preferably, described transition metal is the combination of iron ruthenium, the mol ratio of described iron and ruthenium is 0.01 ~ 0.09, preferably 0.02 ~ 0.03, in the weight of catalyst for 100%, transition metal active component presses transition metal weighing scale, and the percentage by weight of transition metal active component is 0.1 ~ 10%;

Preferably, described transition metal is the combination of iron iridium, the mol ratio of described iron and iridium is 0.01 ~ 0.09, preferably 0.02 ~ 0.03, in the weight of catalyst for 100%, transition metal active component presses transition metal weighing scale, and the percentage by weight of transition metal active component is 0.1 ~ 10%;

Preferably, so adjuvant component is the combination of oxide in alkali metal or alkaline-earth metal or any one or at least two kinds in hydroxide, in the weight of catalyst for 100%, the percentage by weight of adjuvant component is 0.1 ~ 40%, further preferably 0.5 ~ 20%, more further preferably 2 ~ 10%.

9. a purposes for the catalyst as described in one of claim 1-8, is characterized in that, described catalyst is used for room temperature purifying formaldehyde.

10. purposes as claimed in claim 9, it is characterized in that, method catalyst being used for room temperature purifying formaldehyde comprises the steps:

First catalytic purification formaldehyde module is prepared by shaping for fine catalyst, then assembling forms catalytic purification formaldehyde assembly, then put it in air purifier or other air cleaning units, under the perturbation action of air, the dusty gas containing formaldehyde is passed through said apparatus, and and catalytic purification component touch, thus the purification of formaldehyde under realizing room temperature.